Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cay tren » chay tren, ca tren, cau tren
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac tac
dan cua » dan ca, ban cua, dai cua
cua cay » cua cac
ve cac » va cac, vien cac
tuc va » thuc va, truc va, tuc xa
va dan » ca dan, va dao, va dau

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ky nang cao hoi. hieu ve cac tuc va dan cua cay tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky nang cao hoi. hieu ve cac tuc va dan cua cay tren".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky nang cao hoi. hieu ve cac tuc va dan cua cay tren*.